Imprecise Frequency Descriptors and the Miscomprehension of Prescription Drug Advertising: Public Policy and Regulatory Implications

Abstract

Two separate studies, conducted among a total sample of 147 adults, explored the communicative effectiveness of imprecise frequency descriptors within the context of direct to consumer prescription drug advertising. Study One used imprecise frequency descriptors to describe level of side effect occurrence and then asked consumers to numerically estimate the frequency of side effect occurrence. A comparison of consumers' estimated to actual level of incidence indicated that they are unable to accurately estimate level of side effect occurrence when those levels are described by an imprecise frequency descriptor. Study Two presented consumers with a list of side effects preceded by an imprecise frequency descriptor. Consumers were then asked to estimate the relative likelihood of side effect occurrence. The results indicated that consumers are unable to accurately estimate the relative likelihood of side effect occurrence when a list of side effects are preceded by an imprecise frequency descriptor. The pattern of consumer response across both studies indicates that when imprecise frequency descriptors are used to describe the incidence of side effects within the context of direct to consumer prescription drug advertising, consumers estimate likelihood of side effect occurrence on the basis of an intuitive judgment of the side effect's commonness/severity within the general population.